.300WM with 1/12 twist

[SigsauerP229]

Anyone got any load suggestions for a custom .300WM with a Douglas 1/12 twist barrel.

I shot several loads out of this to test before I started building up loads for it.

HSM 210gr. VLD's were the worst with groups over 2".

HSM 208 A-Max were an inch or more but I did 4 shots in 1/2" but the other 3 opened it 1 1/2".

I also shot Corbon and Fed GMM 190's and groups were 3/4" at best and about 1 1/2" at max.

I think the groups I'm getting are signs that this barrel isn't stabalizing the bullet. I loaded up some 175gr. SMK with 77gr. of H1000 but I need to go test it.

Eventually I'll have a 1/10 twist barrel installed but until then I was wondering if anyone has some suggested loads with the 1/12 twist. I'd like to throw the heavier bullets but I don't think it's going to happen with this barrel.

Thanks

 

[MontanaMarine]

Re: .300WM with 1/12 twist

I don't know, my 1/12 308Win shoots 208s, 210s, 225s, all sub-moa at speeds in the 2500-2600 fps range.

I would think at 300WinMag speeds they would be plenty stable from a 1/12 twist.

 

[SigsauerP229]

Re: .300WM with 1/12 twist

Thanks for the reply. Anyone else having luck with 208's or 210's in a 1/12 twist?

I just picked up some Hornady 208 HPBT and 190 SMK's. I have a few loads built up with H1000, but if anyone else has a suggested load, I'd appreciate hearing it.

 

[Jeepocabra]

Re: .300WM with 1/12 twist

My 300wsm is a 12-1 twist. Shoots 208gr Amaxes at 2950 great, but I have a 28" barrel.